情况有点像
var someVar = some_other_function();
someObj.addEventListener("click", function(){
some_function(someVar);
}, false);
问题是someVar的值在addEventListener的侦听器函数中是不可见的,在addEventListener中它可能被视为一个新变量。
情况有点像
var someVar = some_other_function();
someObj.addEventListener("click", function(){
some_function(someVar);
}, false);
问题是someVar的值在addEventListener的侦听器函数中是不可见的,在addEventListener中它可能被视为一个新变量。
当前回答
不错的一行选择
element.addEventListener('dragstart',(evt) => onDragStart(param1, param2, param3, evt));
function onDragStart(param1, param2, param3, evt) {
//some action...
}
其他回答
这里还有另一种方法(它在for循环中工作):
var someVar = some_other_function();
someObj.addEventListener("click",
function(theVar){
return function(){some_function(theVar)};
}(someVar),
false);
因为你的事件监听器是'click',你可以:
someObj.setAttribute("onclick", "function(parameter)");
你需要:
newElem.addEventListener('click', {
handleEvent: function (event) {
clickImg(parameter);
}
});
向eventListener的回调函数发送参数需要创建一个隔离函数并将参数传递给该隔离函数。
这里有一个很好的辅助函数。基于上面“hello world”的例子。)
还有一件事是维护对函数的引用,这样我们就可以干净地删除侦听器。
// Lambda closure chaos.
//
// Send an anonymous function to the listener, but execute it immediately.
// This will cause the arguments are captured, which is useful when running
// within loops.
//
// The anonymous function returns a closure, that will be executed when
// the event triggers. And since the arguments were captured, any vars
// that were sent in will be unique to the function.
function addListenerWithArgs(elem, evt, func, vars){
var f = function(ff, vv){
return (function (){
ff(vv);
});
}(func, vars);
elem.addEventListener(evt, f);
return f;
}
// Usage:
function doSomething(withThis){
console.log("withThis", withThis);
}
// Capture the function so we can remove it later.
var storeFunc = addListenerWithArgs(someElem, "click", doSomething, "foo");
// To remove the listener, use the normal routine:
someElem.removeEventListener("click", storeFunc);
一个简单的方法就是这样
window.addEventListener('click', (e) => functionHandler(e, ...args));
对我有用。